<?php
/**
 * Class MinifyHTML
 *
 * @package Minify
 */

/**
 * Compress HTML
 *
 * This is a heavy regex-based removal of whitespace, unnecessary comments and
 * tokens. IE conditional comments are preserved. There are also options to have
 * STYLE and SCRIPT blocks compressed by callback functions.
 *
 * A test suite is available.
 *
 * @package Minify
 * @author  Stephen Clay <steve@mrclay.org>
 */
class MinifyHTML {

	/**
	 * Defines which class to call as part of callbacks, change this
	 * if you extend MinifyHTML
	 *
	 * @var string
	 */
	protected static $className = 'MinifyHTML';

	/**
	 * "Minify" an HTML page
	 *
	 * @param string $html
	 *
	 * @param array  $options
	 *
	 * 'cssMinifier' : (optional) callback function to process content of STYLE
	 * elements.
	 *
	 * 'jsMinifier' : (optional) callback function to process content of SCRIPT
	 * elements. Note: the type attribute is ignored.
	 *
	 * 'xhtml' : (optional boolean) should content be treated as XHTML1.0? If
	 * unset, minify will sniff for an XHTML doctype.
	 *
	 * @return string
	 */

	/* PrestaShop
			 added a limit for all preg_replace_callback
	 */
	public static function minify($html, $options = array()) {

		if (isset($options['cssMinifier']))
		{
			self::$_cssMinifier = $options['cssMinifier'];
		}
		if (isset($options['jsMinifier']))
		{
			self::$_jsMinifier = $options['jsMinifier'];
		}

		$html = str_replace("\r\n", "\n", trim($html));

		self::$_isXhtml = (isset($options['xhtml']) ? (bool)$options['xhtml'] : (false !== strpos($html, '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML')));

		self::$_replacementHash = 'MINIFYHTML' . md5(time());
		self::$_placeholders = array();

		// replace SCRIPTs (and minify) with placeholders
		$html = preg_replace_callback('/\\s*(<script\\b[^>]*?>)([\\s\\S]*?)<\\/script>\\s*/i', array(self::$className, '_removeScriptCB'), $html, Media::getBackTrackLimit());

		// replace STYLEs (and minify) with placeholders
		$html = preg_replace_callback('/\\s*(<style\\b[^>]*?>)([\\s\\S]*?)<\\/style>\\s*/i', array(self::$className, '_removeStyleCB'), $html, Media::getBackTrackLimit());

		// remove HTML comments (not containing IE conditional comments).
		$html = preg_replace_callback('/<!--([\\s\\S]*?)-->/', array(self::$className, '_commentCB'), $html, Media::getBackTrackLimit());

		// replace PREs with placeholders
		$html = preg_replace_callback('/\\s*(<pre\\b[^>]*?>[\\s\\S]*?<\\/pre>)\\s*/i', array(self::$className, '_removePreCB'), $html, Media::getBackTrackLimit());

		// replace TEXTAREAs with placeholders
		$html = preg_replace_callback('/\\s*(<textarea\\b[^>]*?>[\\s\\S]*?<\\/textarea>)\\s*/i', array(self::$className, '_removeTaCB'), $html, Media::getBackTrackLimit());

		// trim each line.
		// @todo take into account attribute values that span multiple lines.
		$html = preg_replace('/^\\s+|\\s+$/m', '', $html, Media::getBackTrackLimit());

		// remove ws around block/undisplayed elements
		$html = preg_replace('/\\s+(<\\/?(?:area|base(?:font)?|blockquote|body' . '|caption|center|cite|col(?:group)?|dd|dir|div|dl|dt|fieldset|form' . '|frame(?:set)?|h[1-6]|head|hr|html|legend|li|link|map|menu|meta' . '|ol|opt(?:group|ion)|p|param|t(?:able|body|head|d|h||r|foot|itle)' . '|ul)\\b[^>]*>)/i', '$1', $html, Media::getBackTrackLimit());

		// remove ws outside of all elements
		$html = preg_replace_callback('/>([^<]+)</', array(self::$className, '_outsideTagCB'), $html, Media::getBackTrackLimit());

		// use newlines before 1st attribute in open tags (to limit line lengths)
		//$html = preg_replace('/(<[a-z\\-]+)\\s+([^>]+>)/i', "$1\n$2", $html);

		// fill placeholders
		$html = str_replace(array_keys(self::$_placeholders), array_values(self::$_placeholders), $html);
		self::$_placeholders = array();

		self::$_cssMinifier = self::$_jsMinifier = null;

		return $html;
	}

	protected static function _commentCB($m) {
		return (0 === strpos($m[1], '[') || false !== strpos($m[1], '<![')) ? $m[0] : '';
	}

	protected static function _reservePlace($content) {
		$placeholder = '%' . self::$_replacementHash . count(self::$_placeholders) . '%';
		self::$_placeholders[$placeholder] = $content;

		return $placeholder;
	}

	protected static $_isXhtml = false;
	protected static $_replacementHash = null;
	protected static $_placeholders = array();
	protected static $_cssMinifier = null;
	protected static $_jsMinifier = null;

	protected static function _outsideTagCB($m) {
		return '>' . preg_replace('/^\\s+|\\s+$/', ' ', $m[1], Media::getBackTrackLimit()) . '<';
	}

	protected static function _removePreCB($m) {
		return self::_reservePlace($m[1]);
	}

	protected static function _removeTaCB($m) {
		return self::_reservePlace($m[1]);
	}

	protected static function _removeStyleCB($m) {
		$openStyle = $m[1];
		$css = $m[2];
		// remove HTML comments
		$css = preg_replace('/(?:^\\s*<!--|-->\\s*$)/', '', $css, Media::getBackTrackLimit());

		// remove CDATA section markers
		$css = self::_removeCdata($css);

		// minify
		$minifier = self::$_cssMinifier ? self::$_cssMinifier : 'trim';
		$css = call_user_func($minifier, $css);

		return self::_reservePlace(self::_needsCdata($css) ? "{$openStyle}/*<![CDATA[*/{$css}/*]]>*/</style>" : "{$openStyle}{$css}</style>");
	}

	protected static function _removeScriptCB($m) {
		$openScript = $m[1];
		$js = $m[2];

		// remove HTML comments (and ending "//" if present)
		$js = preg_replace('/(?:^\\s*<!--\\s*|\\s*(?:\\/\\/)?\\s*-->\\s*$)/', '', $js, Media::getBackTrackLimit());

		// remove CDATA section markers
		$js = self::_removeCdata($js);

		// minify
		$minifier = self::$_jsMinifier ? self::$_jsMinifier : 'trim';
		$js = call_user_func($minifier, $js);

		return self::_reservePlace(self::_needsCdata($js) ? "{$openScript}/*<![CDATA[*/{$js}/*]]>*/</script>" : "{$openScript}{$js}</script>");
	}


	protected static function _removeCdata($str) {
		return (false !== strpos($str, '<![CDATA[')) ? str_replace(array('<![CDATA[', ']]>'), '', $str) : $str;
	}

	protected static function _needsCdata($str) {
		return (self::$_isXhtml && preg_match('/(?:[<&]|\\-\\-|\\]\\]>)/', $str));
	}
}

